Smoking Vents - Blower Motor Wiring?

[madstudios]

Hi everyone!
I'm having some problems with my AC.
When I turn on the AC, it blows cold and fan is working well. But after 10 minutes of usage, no matter the speed of the fan, i can smell something, like burn plastic, and a smoke start to come out of the vents!
When I turn of the ac and motor blower, the smell and smoke stops.
Could be a bad motor blower?
I was confused about the wiring on the blower motor. There is one plug that is not connected, the only place to plug is on the ground, but it come out from the positive wire, so I've left the way it is.
Thank you!



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[Mark D]

If I'm reading the schematic correctly that disconnected wire in the photo should be connected to the blower motor ground terminal that has the open blade at the top of your photo. I'm not sure if it has anything to do with the cause of the smoke, but it looks like it's a power wire that runs parallel to the motor through an inline diode and then to ground. One of the electrical guru's on the board should be able to give you a better idea of what function the wire actually serves. I think it has something to do with preventing power draw through the fan when it's turned off, so I don't really think it should have anything to do with your smoke issue.

[madstudios]

If I'm reading the schematic correctly that disconnected wire in the photo should be connected to the blower motor ground terminal that has the open blade at the top of your photo. I'm not sure if it has anything to do with the cause of the smoke, but it looks like it's a power wire that runs parallel to the motor through an inline diode and then to ground. One of the electrical guru's on the board should be able to give you a better idea of what function the wire actually serves. I think it has something to do with preventing power draw through the fan when it's turned off, so I don't really think it should have anything to do with your smoke issue.

Thanks Mark!
I was wondering what could cause the smoke, besides the blower motor itself... there isn't much eletrical stuff going on in there I suppose.


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[David T]

That wire goes to the black thingy which is a .5 mf capacitor and then to the ground terminal. Meant to filter out electrical noise for the radio from the motor's brushes. Has nothing to do with the smoke or smell. From your description it sounds like the motor is dying. I would pull the motor out and examine it. One possibility is the plastic squirrel cage fan is rubbing on something and causing the smell. The motor looks pretty clean so I wonder that it is not the motor but something else. There is a resistor block for the different fan speeds. It is that plug next tot he fan motor. Pull it too and see if anything is on it and burning. That resistor can get very hot. When you get the motor out look inside the heater box and clean it out. Maybe some old foam got caught in the wrong place.

[Bitsyncmaster]

If you had something on the "speed" resistor, that could cause the smoking. You would need to pull that resistor out to look at it.

[madstudios]

That wire goes to the black thingy which is a .5 mf capacitor and then to the ground terminal. Meant to filter out electrical noise for the radio from the motor's brushes. Has nothing to do with the smoke or smell. From your description it sounds like the motor is dying. I would pull the motor out and examine it. One possibility is the plastic squirrel cage fan is rubbing on something and causing the smell. The motor looks pretty clean so I wonder that it is not the motor but something else. There is a resistor block for the different fan speeds. It is that plug next tot he fan motor. Pull it too and see if anything is on it and burning. That resistor can get very hot. When you get the motor out look inside the heater box and clean it out. Maybe some old foam got caught in the wrong place.

Here is the photo of my resistor...


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[Bitsyncmaster]

Here is the photo of my resistor...


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Looks clean. So it must be your blower motor smoking.

[AugustneverEnds]

There might be something trapped in the cage in the blower motor. Mice nests and other nasty things can find their way in there. Worth checking out

[Bob635]

If you can check the amps the motor is drawn when you first turn it on and then when you start smelling the electrical odor, this might confirm that the windings on the motor are shorting.
Higher amps when it is hot is a symptom of shorted motor wiring.
Bob

Hi everyone!
I'm having some problems with my AC.
When I turn on the AC, it blows cold and fan is working well. But after 10 minutes of usage, no matter the speed of the fan, i can smell something, like burn plastic, and a smoke start to come out of the vents!
When I turn of the ac and motor blower, the smell and smoke stops.
Could be a bad motor blower?
I was confused about the wiring on the blower motor. There is one plug that is not connected, the only place to plug is on the ground, but it come out from the positive wire, so I've left the way it is.
Thank you!



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[madstudios]

After a good cleaning in the blower and resistor, I've run the ac about 40 minutes and Everything looks ok now!
Tomorrow I'll test again...
Thanks!



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